FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Mar. 31, 2015
ASSETS:
Cash and cash equivalents	$ 94,352	$ 104,893
Marketable securities	173,160	159,964
Derivative financial instruments	97	15
Total assets	267,609	264,872
LIABILITIES:
Contingent purchase consideration	(4,521)	(4,484)
Derivative financial instruments	(456)	(1,664)
Total liabilities	(4,977)	(6,148)
U.S. government and municipal obligations
ASSETS:
Marketable securities	160,086	145,345
Commercial paper
ASSETS:
Marketable securities	5,099	5,095
Corporate bonds
ASSETS:
Marketable securities	7,975	9,524
Level 1
ASSETS:
Cash and cash equivalents	94,352	104,893
Derivative financial instruments	0	0
Total assets	161,096	160,981
LIABILITIES:
Contingent purchase consideration	0	0
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Marketable securities	58,769	46,564
Level 1 | Commercial paper
ASSETS:
Marketable securities	0	0
Level 1 | Corporate bonds
ASSETS:
Marketable securities	7,975	9,524
Level 2
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	97	15
Total assets	106,513	103,891
LIABILITIES:
Contingent purchase consideration	0	0
Derivative financial instruments	(456)	(1,664)
Total liabilities	(456)	(1,664)
Level 2 | U.S. government and municipal obligations
ASSETS:
Marketable securities	101,317	98,781
Level 2 | Commercial paper
ASSETS:
Marketable securities	5,099	5,095
Level 2 | Corporate bonds
ASSETS:
Marketable securities	0	0
Level 3
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	0	0
Total assets	0	0
LIABILITIES:
Contingent purchase consideration	(4,521)	(4,484)
Derivative financial instruments	0	0
Total liabilities	(4,521)	(4,484)
Level 3 | U.S. government and municipal obligations
ASSETS:
Marketable securities	0	0
Level 3 | Commercial paper
ASSETS:
Marketable securities	0	0
Level 3 | Corporate bonds
ASSETS:
Marketable securities	$ 0	$ 0